Method of processing target substrate

ABSTRACT

A method of processing a target substrate includes a process of serially executing multiple processes including a main process and first to M-th subprocesses (where M is a positive integer). An index value indicating one execution of the main process is accumulated for each execution of the main process. The main process is executed multiple times in the process of serially executing multiple processes. An i-th subprocess (where i is a positive integer that satisfies 1≤i≤M) is executed once or multiple times in the process of serially executing multiple processes, and is executed subsequent to one or multiple consecutive executions of the main process. The i-th application and execution conditions are changeable.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on and claims the benefit of priority from Japanese Patent Application No. 2017-197024, filed on Oct. 10, 2017, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a method of processing a target substrate.

BACKGROUND

In a manufacturing process of a semiconductor device, various processes such as etching, film formation, and the like are sequentially executed on a wafer. Before and after the manufacturing process, the interior of a process chamber is cleaned. After the execution of each process, a gas used for the execution of the process is purged.

A technique for shortening the gas cleaning preparation time and improving the throughput by changing from a gas cleaning process that is performed for every single lot to a gas cleaning process that is performed for every two or more lots has been disclosed. Further, a technique of performing the cleaning for each type of process by performing the cleaning according to the type of process has been disclosed. In addition, a technique intended to perform the cleaning under an appropriate cleaning condition and at an appropriate timing when switching lots has been disclosed.

When multiple processes are serially executed in the manufacturing process of a semiconductor device, an execution aspect of each process such as the order of executing the process, the timing of executing the process, or the like may affect the manufacturing efficiency or the like of the semiconductor device. Therefore, when multiple processes are serially executed, there is a desire for a technique capable of flexibly setting an execution aspect of each process such as the order of executing the process, the timing of executing the process, or the like.

SUMMARY

Some embodiments of the present disclosure provide a method of processing a target substrate. The method includes a process of serially executing multiple processes including a main process and first to M-th subprocesses (where M is a positive integer), wherein an index value indicating one execution of the main process is accumulated for each execution of the main process, the main process is executed multiple times in the process of serially executing multiple processes, an i-th subprocess (where i is a positive integer that satisfies 1≤i≤M) is executed once or multiple times in the process of serially executing multiple processes, the i-th subprocess is executed subsequent to one or multiple consecutive executions of the main process, the i-th subprocess is applied to the process of serially executing multiple processes when a cumulative value of the index value accumulated from a start of the process of serially executing multiple processes satisfies an i-th application condition, when the cumulative value of the index value accumulated from the start of the process of serially executing multiple processes satisfies the i-th application condition, the i-th subprocess is executed at a time when a cumulative value of the index value accumulated from execution of a last executed subprocess when there is a subprocess already executed from the start of the process of serially executing multiple processes or a cumulative value of the index value accumulated from the start of the process of serially executing multiple processes when there is no subprocess already executed from the start of the process of serially executing multiple processes satisfies an i-th execution condition, and both the i-th application condition and the i-th execution condition are changeable.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present disclosure, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the present disclosure.

FIG. 1 is a flowchart illustrating a part of a method according to one embodiment of the present disclosure.

FIG. 2 is a diagram illustrating an example of a configuration of a processing apparatus in which the method illustrated in FIG. 1 is executed.

FIG. 3 is a diagram illustrating an example of an execution state of a process illustrated in FIG. 1.

FIG. 4 is a flowchart more specifically illustrating the flowchart illustrated in FIG. 1.

FIG. 5 is a diagram more specifically illustrating an execution state of the process illustrated in FIG. 3.

DETAILED DESCRIPTION

Reference will now be made in detail to various embodiments, examples of which are illustrated in the accompanying drawings. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be apparent to one of ordinary skill in the art that the present disclosure may be practiced without these specific details. In other instances, well-known methods, procedures, systems, and components have not been described in detail so as not to unnecessarily obscure aspects of the various embodiments.

Various embodiments will now be described in detail with reference to the drawings. Further, like or equivalent parts in the respective drawings are given like reference numerals. FIG. 1 is a flowchart of a process A illustrating a part of a method MT according to one embodiment of the present disclosure. The method MT illustrated in FIG. 1 is a method of processing a target substrate (hereinafter, referred to as a “wafer W”). The process A included in the method MT according to one embodiment may be executed using a processing apparatus 1 illustrated in FIG. 2. FIG. 2 is a diagram illustrating an example of a configuration of the processing apparatus 1 in which the method illustrated in FIG. 1 is executed.

The processing apparatus 1 includes carrier mounting ports 11, an atmospheric transfer chamber 12, a load lock module LLM1, a load lock module LLM2, a vacuum transfer chamber 13, a processing module PM1, a processing module PM2, a processing module PM3, and a processing module PM4. The atmospheric transfer chamber 12, the load lock module LLM1, the load lock module LLM2, the vacuum transfer chamber 13, the processing module PM1, the processing module PM2, the processing module PM3, and the processing module PM4 (the processing modules PM1 to PM4) are sequentially arranged in a loading direction of the wafer W, and are connected to each other while maintaining airtightness via a door G1, a door valve G2, a gate valve G3, and a gate valve G4.

A transfer container C is loaded on each of the carrier mounting ports 11. The carrier mounting port 11 corresponds to a loading port of the transfer container C. The transfer container C accommodates a plurality of wafers W. The transfer container C is connected to the atmospheric transfer chamber 12 via the door G1.

The atmospheric transfer chamber 12 transfers the wafers W discharged from the transfer container C under an air atmosphere. A transfer arm 121 is installed in the atmospheric transfer chamber 12. The transfer arm 121 can freely rotate, extend and contract, move up and down, and move left and right. The transfer arm 121 takes out the wafers W one by one from the transfer container C and transfers the taken-out wafers W. An alignment chamber 14 is installed on the side surface of the atmospheric transfer chamber 12. The alignment chamber 14 incorporates an orienter for aligning the wafers W.

Each of the load lock module LLM1 and the load lock module LLM2 is connected to the atmospheric transfer chamber 12 via the door valve G2. In both of the load lock module LLM1 and the load lock module LLM2, their respective internal states are switched between an air atmosphere and a preliminary vacuum atmosphere to allow the wafers W to be in a standby state. Both the load lock module LLM1 and the load lock module LLM2 are disposed so as to connect between the atmospheric transfer chamber 12 and the vacuum transfer chamber 13. A vacuum pump and a leak valve (not shown) for switching the interior of each of the load lock module LLM1 and the load lock module LLM2 between the air atmosphere and the vacuum atmosphere are connected to each of the load lock module LLM1 and the load lock module LLM2. A mounting table 16 is installed in each of the load lock module LLM1 and the load lock module LLM2. The mounting table 16 mounts the carried-in wafers W thereon.

The vacuum transfer chamber 13 is connected to each of the load lock module LLM1 and the load lock module LLM2 via the gate valve G3. The vacuum transfer chamber 13 transfers the wafers W under a vacuum atmosphere. The processing modules PM1 to PM4 are connected to the vacuum transfer chamber 13 via gate valves G4. The vacuum pump (not shown) for maintaining the interior of the vacuum transfer chamber 13 in a vacuum atmosphere is connected to the vacuum transfer chamber 13.

A transfer arm 131 is installed in the vacuum transfer chamber 13. The transfer arm 131 can freely rotate and extend and contract. The transfer arm 131 transfers the wafers W between the load lock module LLM1, the load lock module LLM2, and the processing modules PM1 to PM4.

The processing modules PM1 to PM4 all execute a process on the wafers W. Each of the processing modules PM1 to PM4 has a process container PS which accommodates the wafers W, in which the process is performed on the wafers W accommodated in the process container PS.

Each of the processing modules PM1 to PM4 can execute, for example, a different type of process, on the wafers W. In one embodiment, for example, the processing module PM1 and the processing module PM2 may be film forming modules for forming a thin film on the surfaces of the wafers W arranged in the process containers PS. In one embodiment, for example, the processing module PM3 and the processing module PM4 may be plasma processing modules for generating plasma in the process containers PS and performing plasma processing on a thin film on the surfaces of the wafers W arranged in the process containers PS.

The processing apparatus 1 further includes a controller 2. The controller 2 comprehensively controls an operation of each part (the transfer arm 121 or the like illustrated in FIG. 1) of the processing apparatus 1. The controller 2 may be configured as a computer device including a processor 2 a, a memory 2 b, a storage 2 c, a communication device 2 d, an input device 2 e, an output device 2 f, a bus 2 g, and the like. The processor 2 a, the memory 2 b, the storage 2 c, the communication device 2 d, the input device 2 e, the output device 2 f, and the like are mutually connected via the bus 2 g.

The operation of each part of the processing apparatus 1 is realized by reading a computer program (for example, a program for executing a process A) stored in the storage 2 c or the like or a computer program downloaded from an external device via the communication device 2 d into the processor 2 a and the memory 2 b and causing the processor 2 a to execute the computer program. The processor 2 a may include a central processing unit (CPU), a memory, and the like.

The memory 2 b is a computer-readable recording medium. The memory 2 b may be configured to include at least one of, for example, a read only memory (ROM), an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a random access memory (RAM), and the like.

The storage 2 c is a computer-readable recording medium. The storage 2 c can be accessed by the processor 2 a. The storage 2 c may be configured to include at least one of, for example, an optical disc, a hard disk drive, and the like.

The communication device 2 d is a transceiver device for performing communication between computers via a wired and/or wireless network. The communication device 2 d is, for example, a network device, a network controller, a network card, a communication module, or the like.

The input device 2 e is an input device (for example, a keyboard, a mouse, a microphone, a switch, a button, a sensor, or the like) that accepts an input from the outside. The output device 2 f is an output device (for example, a display, a speaker, an LED lamp, or the like) for performing outputting to the outside. The input device 2 e and the output device 2 f may be integrally configured (for example, a touch panel).

An operation of processing the wafers W by the processing apparatus 1 described above will be schematically described. The wafers W accommodated in the transfer container C on the carrier mounting port 11 are discharged by the transfer arm 121 and positioned in the alignment chamber 14 during the transfer through the atmospheric transfer chamber 12, and then transferred to one of the load lock modules LLM1 and the load lock modules LLM2.

After the wafers W are transferred to one of the load lock module LLM1 and the load lock module LLM2, when the interior of each of the load lock module LLM1 and the load lock module LLM2 becomes a preliminary vacuum atmosphere, the wafers W are discharged by the transfer arm 131 and transferred into the vacuum transfer chamber 13. Thereafter, the wafers W are transferred between the vacuum transfer chamber 13 and the processing modules PM1 to PM4, and processed in the processing modules PM1 to PM4. The processed wafers W are accommodated in the transfer container C through a reverse path (excluding the alignment chamber 14) of the loading path.

Next, the method MT according to one embodiment of the present disclosure will be described. The method MT is a method of processing a plurality of wafers W. The method MT is executed under the control of the controller 2. The method MT includes a process A. The process A serially executes multiple processes including a main process and first to M-th subprocesses (where M is a positive integer in the present disclosure) in the process container PS. The content of the main process and the content of each of the first to M-th subprocesses are set in advance in the controller 2 via the input device 2 e. The execution times of the first to M-th subprocesses may be different from each other. The processes being serially executed means that multiple processes are executed sequentially (serially), more specifically, that the execution of a next process starts at the time when the execution of one process is ended.

In one embodiment, for example, the main process processes a single wafer W. The main process is executed serially multiple times in the process A. The main process is, for example, a process performed on the wafers W arranged in the process container PS by supplying a gas into the process container PS, and may be a film forming process, an etching process, or the like.

An i-th subprocess (where i is a positive integer that satisfies 1≤i≤M in the present disclosure) is executed once or multiple times in the process A. The i-th subprocess is executed subsequent to one or multiple consecutive executions (corresponding to the i-th unit lot) of the main process in the process A. In the process A, interruption of the first to M-th subprocesses occurs in the process where the main processes are sequentially executed. In other words, in the process where the main process is sequentially executed, the main process is executed immediately before the execution of the i-th subprocess, and the main process is also executed immediately after the execution of the i-th subprocess. The i-th subprocess may be, for example, a process of purging the interior of the process container PS.

In the process A, an index value N1 indicating one execution of the main process is accumulated for each execution of the main process. A cumulative value of the index value N1 accumulated from the start of the process A is set as a cumulative value α. The cumulative value α at the start of the process A satisfies α=0.

The index value N1 may be one of the number of wafers W processed by one execution of the main process or a thickness of a film formed on the wafers W by one execution of the main process when the main process is a film forming process, the number of cycles and a plasma generating time, or a combination thereof. When the number of wafers W processed by one execution of the main process is 1, N1=1 [sheet]. When the thickness of a film formed on the wafers W by one execution of the main process is, for example, 10 nm, N1=10 [nm]. Other units such as Angstrom may also be used as the unit of film thickness. The index value N1 is set in advance in the controller 2 via the input device 2 e before the execution of the method MT.

A reference value N2 is a value for determining the completion (End) of the process A based on the cumulative value α, and is set in advance in the controller 2 via the input device 2 e before the execution of the method MT. The reference value N2 is a total number (upper limit value) of the number of wafers W processed in the process A when the index value N1 is the number of wafers W processed by one execution of the main process. In the case where the index value N1 is the thickness of a film formed on the wafers W by one execution of the main process when the main process is the film forming process, the reference value N2 is a total thickness number (upper limit value) of a film formed on the wafers W in the process A.

For the application of the i-th subprocess in the process A, the i-th subprocess is applied to the process A when the cumulative value α satisfies an i-th application condition. For the execution of the i-th subprocess, the i-th subprocess is executed at the time when a total value of the index value N1 obtained by one or multiple consecutive executions of the main process (corresponding to the i-th unit lot) satisfies an i-th execution condition when the cumulative value α satisfies the i-th application condition.

When i=k (where k is a positive integer that satisfies 1≤k≤M−1 in the present disclosure), a k-th application condition is that the cumulative value α satisfies L(k−1)<α≤L(k). L(k−1) and L(k) are values for defining the range of the cumulative value α as the k-th application condition, and are real numbers of 0 or more. L(0)=0 and L(k−1)<L(k) are each satisfied. For example, when the cumulative value α indicates a cumulative value of the number of wafers W, L(k−1) and L(k) are values [sheets] indicating the number of wafers W, and when the cumulative value α indicates a cumulative value of film thickness, they are values [nm] indicating a film thickness. When i=M, an M-th application condition is an application condition of the M-th subprocess that is last applied in the process A among the first to M-th subprocesses, and satisfies L(M−1)<α.

The i-th execution condition is that a total value β of the index value N1 accumulated from the execution of a subprocess last executed when there is a subprocess already executed from the start of the process A, or a total value β of the index value N1 accumulated from the start of the process A when there is no subprocess already executed from the start of the process A satisfies β>K(i). Here, K(i) is a positive real number, and defines an execution period of the i-th subprocess.

Both the content of the i-th application condition and the content of the i-th execution condition are set in advance in the controller 2 via the input device 2 e before the execution of the method MT. The content of the i-th application condition and the content of the i-th execution condition are all changeable. More specifically, both L(i) and K(i) are set in advance in the controller 2 via the input device 2 e before the execution of the method MT. In particular, L(M)=0 is set for L(M) which is included in the M-th application condition of the M-th subprocess that is last applied in the process A among the first to M-th subprocesses. In other words, i when L(i)=0 is set to i=M. The contents of L(i) and K(i) are all changeable.

The process A will be described in detail with reference to FIGS. 1 and 3. FIG. 1 is a flowchart illustrating a part (process A) of the method MT according to one embodiment of the present disclosure. FIG. 3 is a diagram illustrating an example of an execution state of the process A illustrated in FIG. 1. The horizontal axis in FIG. 3 indicates a cumulative value α of the index value N1 from the start of the process A to the completion (End) of the process A. As illustrated in FIG. 1, the process A includes steps ST1 to ST10. In step ST1, when the process A starts, initial values of three variables (α, β, i) used for the execution of the process A are set. That is, they are set as: α=0, β=0, and i=1.

The index value N1 is added to both of the cumulative value α (α+N1→α) and the total value β (β+N1→β) in one of step ST2 subsequent to step ST1, step ST2 subsequent to step ST8 (“YES”) and step ST2 subsequent to step ST10. In step ST3 subsequent to step ST2, the main process is executed. The main process is executed once in step ST3 and the index value N1 indicating this one execution of the main process is added to the cumulative value α and the total value β in step ST2. In this manner, in the process A, α and β each increases by N1 each time the main process is executed once.

In step ST4 subsequent to step ST3, it is determined whether or not the i-th subprocess currently being applied is a subprocess which is last applied in the process A. More specifically, in step ST 4, it is determined whether L(i)=0 (i=M) is satisfied. In step ST5 subsequent to step ST4 (“NO”), it is determined whether or not to continuously apply the currently applied i-th subprocess. More specifically, in step ST5, it is determined whether or not L(i−1)<α≤L(i) (L(0)=0, i<M) is satisfied. That is, in step ST4 and step ST5, it is determined which of the first to M-th subprocesses is being applied to the process A.

When L(i)=0 is satisfied in step ST4 (step ST4: “YES”), it is determined that at this point i=M and the M-th subprocess is applied to the process A. In step ST6 subsequent to step ST4 (“YES”), it is determined whether or not to continue the process A. More specifically, in step ST6, it is determined whether or not α≤N2 is satisfied. When it is determined in step ST6 that α≤N2 is not satisfied (step ST6: “NO”), the process A is ended, and when it is determined in step ST6 that α≤N2 is satisfied (step ST6: “YES”), the process after step ST8 is performed without ending the process A.

In the case of step ST6 (“NO”), after the end of the process A, a process different from the i-th subprocess used in the process A may be executed, and then the process A may be repeatedly performed again.

In step ST4, when L(i)=0 is not satisfied (step ST4: “NO”), i<M is set. When L(i−1)<α≤L (i) (L(0)=0, i<M) is satisfied (step ST5: “YES”) in step ST5 subsequent to step ST4 (“NO”), it is determined that at this point the i-th subprocess is applied to the process A.

In step ST5, when L(i−1)<α≤L(i) (L(0)=0, i<M) is not satisfied (step ST5: “NO”), at this point, the i-th subprocess is not applied to the process A, and thus, in step ST7 subsequent to step ST5 (“NO”), an i+1 subprocess subsequent to the i-th subprocess is applied to the process A. When step ST7 is executed, the value of i is incremented (increased by 1) (i+1→i), and step ST4 is executed again.

An interval TR(i) illustrated in FIG. 3 is an interval at which the i-th subprocess is applied to the process A, and an interval TR(i+1) illustrated in FIG. 3 is an interval at which the i+1 subprocess is applied to the process A. The transition from the interval TR(i) to the interval TR(i+1) illustrated in FIG. 3 is realized by incrementing i executed in step ST7. An interval TR(1), an interval TR(2), an interval TR(M−1), and an interval TR(M) illustrated in FIG. 3 are similar to the case of the intervals TR(i) and TR(i+1).

In step ST8 subsequent to step ST5 (“YES”), it is determined whether or not the execution timing of the currently applied i-th subprocess is reached. More specifically, in step ST8, it is determined whether or not the total value β satisfies β≤K(i). Here, K(i) defines the execution period of the i-th subprocess. Therefore, in step ST8, it is determined whether or not the i-th subprocess is executed.

When β≤K(i) is satisfied (step ST8: “YES”), it is determined that the i-th subprocess is not executed (the execution period of the i-th subprocess is not reached). In the case of step ST8 (“YES”), the process proceeds to step ST2 and step ST3 where the main process is further executed. When β≤K(i) is not satisfied (step ST8: “NO”), it is determined that the execution timing of the currently applied i-th subprocess has been reached. That is, in step ST8 (“NO”), it is determined that the i-th subprocess is executed. In the case of step ST8 (“NO”), the process proceeds to step ST9 where the i-th subprocess is executed.

A timing SP(i) illustrated in FIG. 3 corresponds to the case where it is determined in step ST8 that β≤K(i) is not satisfied, and corresponds to the execution timing of the i-th subprocess. A timing SP(1), a timing SP(2), a timing SP(i+1), a timing SP(M−1) and a timing SP(M) illustrated in FIG. 3 are similar to the case of the timing SP(i).

Since the i-th subprocess has been executed in step ST9, the total value β is reset to a value of zero (0→β) in step ST10 subsequent to step ST9. In a state in which the total value β is reset to zero, each process after step ST2 is repeated, and it is determined again in step ST8 whether or not β>K(i) is satisfied (it is determined whether or not the i-th execution condition is satisfied).

EXAMPLES

An example of the process A will be described with reference to FIGS. 4 and 5. FIG. 4 and FIG. 5 may be diagrams illustrating the same example. FIG. 4 is a flowchart more specifically illustrating the flowchart illustrated in FIG. 1. The process A illustrated in FIG. 4 includes steps ST1 a to ST7 a. FIG. 5 is a diagram more specifically illustrating an execution state of the process A illustrated in FIG. 3. FIG. 5 illustrates an execution state of the process A corresponding to the flowchart illustrated in FIG. 4.

When the execution of the process A illustrated in FIG. 4 starts, step ST1 illustrated in FIG. 1 is executed, and thereafter, step ST1 a is executed. Step ST1 a corresponds to step ST2 and step ST3 illustrated in FIG. 1, and step ST2 a corresponds to step ST4 illustrated in FIG. 1. Step ST3 a corresponds to step ST5 illustrated in FIG. 1, step ST4 a corresponds to step ST6 illustrated in FIG. 1, and step ST5 a corresponds to step ST7 illustrated in FIG. 1. Step ST6 a corresponds to step ST8 illustrated in FIG. 1, and step ST7 a corresponds to step ST9 and step ST10 illustrated in FIG. 1.

In one example illustrated in FIGS. 4 and 5, the main process is a wafer process for processing a wafer W using a gas (further using plasma), such as, for example, a film forming process or an etching process, and the i-th subprocess is a purge process for purging the interior of the process container PS in which the wafer processing process has been performed. In one example illustrated in FIGS. 4 and 5, the process A can be performed after the process of cleaning the interior of the process container PS using, for example, a ClF₃ gas.

In one example illustrated in FIGS. 4 and 5, the index value N1 is a thickness [nm] of a film formed on the wafer W by one wafer process (main process). Therefore, both the cumulative value α and the total value β correspond to a cumulative value [nm] of film thickness. Since L(i) used for the i-th application condition (see step ST5 illustrated in FIG. 1) is also a value for defining the range of the cumulative value α, similar to the cumulative value α, it corresponds to a value [nm] of the film thickness. Since K(i) used for the i-th execution condition (see step ST8 illustrated in FIG. 1) is also a value for defining the range of the total value β, similar to the total value β, it corresponds to a value [nm] of the film thickness. For example, as illustrated in FIG. 5, there may be L(1)=3,000 [nm], K(1)=700 [nm], and K(2)=500 [nm].

In the process A illustrated in FIG. 4, the wafer process corresponding to the main process is executed in step ST1 a. In step ST2 a subsequent to step ST1 a, it is determined whether or not the purge process corresponding to the currently applied i-th subprocess is a purge process corresponding to the M-th subprocess which is last applied in the process A.

When it is determined in step ST2 a that the currently applied purge process (the i-th subprocess) is not the purge process corresponding to the M-th subprocess which is last applied in the process A (step ST2 a: “NO”), the process proceeds to step ST3 a where it is determined whether or not to continuously apply the purge process corresponding to the currently applied i-th subprocess. In order to determine whether or not to continuously apply the purge process corresponding to the currently applied i-th subprocess in step ST3 a, when i=k (where k is a positive number that satisfies 1≤k≤M−1), a k-th application condition L(k−1)<α≤L(k)) is used (see step ST5 illustrated in FIG. 1).

When it is determined in step ST3 a to continuously apply the purge process corresponding to the currently applied i-th subprocess (step ST3 a: “YES”), the process proceeds to step ST6 a. When it is determined in step ST3 a not to continuously apply the purge process corresponding to the currently applied i-th subprocess (step ST3 a: “NO”), the process proceeds to step ST5 a where the purge process is changed from the purge process corresponding to the currently applied i-th subprocess to a purge process corresponding to an (i+1)th subprocess to be applied next, subsequent to the purge process corresponding to the currently applied i-th subprocess, and after this change, the process returns to step ST2 a.

When it is determined that the purge process corresponding to the currently applied i-th subprocess is the purge process corresponding to the M-th subprocess which is last applied in the process A (step ST2 a: “YES”), the process proceeds to ST4 a where it is determined whether or not to continue the process A. That is, in step ST4 a, it is determined whether or not the cumulative value α exceeds the reference value N2 that is the upper limit value of the number of wafers W processed in step ST4 a (see step ST 6 illustrated in FIG. 1). In step ST4 a, when it is determined not to continue the process A (the cumulative value α has exceeded the reference value N2) (step ST4 a: “NO”), the process A is ended. In step ST4 a, when it is determined to continue the process A (the cumulative value α has not exceeded the reference value N2) (step ST4 a: “YES”), the process proceeds to step ST6 a.

Further, in the case of step ST4 a (“NO”), after the process A is ended, a process (for example, dry cleaning) different from the purge process corresponding to the i-th subprocess used in the process A is executed, and thereafter, the process A may be repeatedly executed.

In step ST6 a, it is determined whether or not the current timing has reached the execution timing (SP(i)) of the purge process corresponding to the i-th subprocess. In step ST6 a, β≤K(i) is used in order to determine whether or not the current timing has reached the execution timing (SP(i)) of the purge process corresponding to the i-th subprocess (see step ST8 illustrated in FIG. 1). When it is determined that the current timing has not reached the execution timing (SP(i)) of the purge process corresponding to the i-th subprocess (step ST6 a: “NO”), the process proceeds to step ST1 a which executes the wafer process, and the processes after step ST1 a are repeated.

When it is determined that the current timing has reached the execution timing (SP(i)) of the purge process corresponding to the i-th subprocess (step ST6 a: “YES”), the process proceeds to step ST7 a which executes the purge process corresponding to the currently applied i-th subprocess. After step ST7 a, the process proceeds to step ST1 a which executes the wafer process to repeat the process after step ST1 a.

For example, as illustrated in FIG. 5, when the cumulative value α of the film thickness accumulated from the start of the process A exceeds L(1) (=3,000 [nm]) which does not satisfy a first application condition (step ST3 a: “NO”), in step ST5 a, the purge process is changed from the purge process corresponding to a first subprocess currently being applied to a purge process corresponding to a second subprocess to be applied next. In this case, after step ST5 a, since the currently applied purge process becomes the purge process corresponding to the second subprocess, K(1) (=700 [nm]) used for determining the execution timing of the purge process in step ST6 a is also changed to K(2) (=500 [nm]), and K(2) is used in this determination of step ST6 a (step ST8 illustrated in FIG. 1).

Therefore, the timing SP(2), in which the purge process corresponding to the second subprocess is first executed after the cumulative value α exceeds L(1), is a timing (the timing when the cumulative value α first exceeds 2,800+K(2)=3,300 [nm]) that the total value β from the timing SP(1) (the timing when the cumulative value α first exceeds 5×K(1)=2,800 [nm]), in which the purge process corresponding to the first subprocess is last executed while the cumulative value α is less than or equal to L(1), first exceeds K(2).

Accordingly, when a cleaning of the process container PS has already been completed at the start of the process A, the execution of the process A progresses such that the frequency and execution time of the purge process for purging the interior of the process container PS are suppressed for a while after the start of the process A. As the effect of cleaning before the start of the process A decreases, the frequency and execution time of the purge process are increased. Thus, it is possible to sufficiently reduce generation of particles over the execution period of the process A.

As described above, since the generation of particles is relatively small in the initial stage of the process A in which the effect of cleaning before the start of the process A is sufficiently maintained, it is possible to reduce a downtime caused by conditioning by suppressing the frequency and execution time of the purge process.

In a situation where the generation of particles can gradually increase as the execution of the process A progresses and the cumulative value α increases, by gradually increasing the number of executions of the purge process corresponding to the i-th subprocess while gradually shortening the execution period of the purge process corresponding to K(i), namely the i-th subprocess, it is possible to strongly execute the purge process within a short period at the end of the process A where the generation of particles tends to increase. As a result, it is possible to sufficiently prolong the execution period of cleaning for the process container PS executed before and after the process A.

According to the aforementioned method MT, since the condition for involving the i-th subprocess in the process A in which multiple main processes are serially executed, namely both the i-th application condition for the i-th subprocess to be applied to the process A and the i-th execution condition for the i-th subprocess to be executed in the process A, can be set to be changeable, when multiple processes are serially executed in the process A, the execution aspect of each process such as the order of executing the process, the timing of executing the process, or the like can be flexibly set.

Furthermore, since the k-th application condition for applying the k-th subprocess when i=k is L(k−1)<α≤L(k) and the M-th application condition for applying the M-th subprocess when i=M is L(M−1)<α, the i-th subprocess can be sequentially applied in the process A as the cumulative value α increases (the increase in the number of wafers W processed by the main process). In addition, the change of the i-th application condition can be realized by changing L(i).

Moreover, since the i-th execution condition for executing the i-th subprocess is β>K(i), where β is the total value β of the index value accumulated from the execution of a subprocess last executed when there is a subprocess already executed from the start of the process A or the total value β of the index value accumulated from the start of the process A when there is no subprocess already executed from the start of the process A, β increases according to the increase in the number of wafers W processed by the main process, and the i-th subprocess can be executed at the time when β exceeds K(i). In addition, the change of the i-th execution condition can be realized by changing K(i).

Furthermore, the i-th application condition for the i-th subprocess to be applied in the process A and the i-th execution condition for the i-th subprocess to be executed in the process A may be appropriately set based on either the number of wafers W processed by one execution of the main process or the thickness of a film formed on the wafers W processed by one execution of the main process when the main process is a film forming process.

In addition, the main process can be a process which is performed on the wafers W arranged in the process container PS by supplying a gas into the process container PS, and the subprocess can be a process of purging the interior of the process container PS. In this case, since the execution timing of the subprocess can be adjusted in the process A in which the main processes are serially executed, the improvement of the effect and reduction of the load due to the purge can be appropriately realized, considering the content of the main process and the content of cleaning that can be executed before and after the process A. For example, in the case where the process A is started using the process container PS after it is cleaned, since the timing immediately after the start of the process A is the timing immediately after the process container PS is cleaned, it is possible to make the execution period of the purge (the execution period of the subprocess) relatively longer and to make one purge time (the execution time of the subprocess) relatively shorter. In addition, as the process A approaches to the end, since deposits or the like may increase in the process container PS according to multiple executions of the main process, it is possible to make the execution period of the purge (the execution period of the subprocess) relatively shorter and to make one purge time (the execution time of the subprocess) relatively longer.

According to the present disclosure in some embodiments, it is possible to provide a technique capable of flexibly setting an execution aspect of each process such as the order of executing the process, the timing of executing the process or the like when multiple processes are serially executed.

While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the disclosures. Indeed, the embodiments described herein may be embodied in a variety of other forms. Furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the disclosures. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the disclosures. 

What is claimed is:
 1. A method of processing a target substrate, comprising: a process of serially executing multiple processes including a main process and first to M-th subprocesses (where M is a positive integer), wherein an index value indicating one execution of the main process is accumulated for each execution of the main process, the main process is executed multiple times in the process of serially executing multiple processes, an i-th subprocess (where i is a positive integer that satisfies 1≤i≤M) is executed once or multiple times in the process of serially executing multiple processes, the i-th subprocess is executed subsequent to one or multiple consecutive executions of the main process, the i-th subprocess is applied to the process of serially executing multiple processes when a cumulative value of the index value accumulated from a start of the process of serially executing multiple processes satisfies an i-th application condition, when the cumulative value of the index value accumulated from the start of the process of serially executing multiple processes satisfies the i-th application condition, the i-th subprocess is executed at a time when a cumulative value of the index value accumulated from execution of a last executed subprocess when there is a subprocess already executed from the start of the process of serially executing multiple processes or a cumulative value of the index value accumulated from the start of the process of serially executing multiple processes when there is no subprocess already executed from the start of the process of serially executing multiple processes satisfies an i-th execution condition, and both the i-th application condition and the i-th execution condition are changeable, and wherein α is the cumulative value of the index value accumulated from the start of the process of serially executing multiple processes and a k-th application condition (where k is a positive integer that satisfies 1≤k≤M) is that the cumulative value α satisfies L(k−1)<α≤L(k), L(k−1) and L(k) are real numbers of 0 or more and satisfy L(k−1)<L(k), and an M-th application condition of the M-th subprocess that is last applied in the process of serially executing multiple processes among the first to M-th subprocesses is that the cumulative value α satisfies L(M−1)<α, wherein the i-th execution condition is that a total value β of the index value accumulated from the execution of the last executed subprocess when there is a subprocess already executed from the start of the process of serially executing multiple processes, or a total value β of the index value accumulated from the start of the process of serially executing multiple processes when there is no subprocess already executed from the start of the process of serially executing multiple processes satisfies β>K(i), and K(i) is a positive real number, wherein L(k−1) and L(k) are values for defining the range of the cumulative value as the k-th application condition, and wherein K(i) defines an execution period of the i-th subprocess.
 2. The method of claim 1, wherein the index value is either the number of target substrates processed by one execution of the main process or a thickness of a film formed on the target substrates by one execution of the main process when the main process is a film forming process.
 3. The method of claim 1, wherein the main process is a process performed on the target substrate arranged in a process container by supplying a gas into the process container, and each of the subprocesses is a process of purging an interior of the process container. 